Dyed slide fastener with stitched-on coupling coil

ABSTRACT

A coupling coil is lockstitched to the longitudinal edge of a support tape with a transparent synthetic-resin mono-filamentary thread overlying the individual coil turns. The coil and the tape are dyed and the thread is left transparent. In this manner the color of the coil is visible through the attachment thread and there is no color contrast apparent between this thread and the rest of the stringer. Heat treatment of the dyed and assembled stringer flattens the monofilament over the coil to attach the coil securely to the tape and to make the thread blend in as much as possible. A single needle Type 401 or a double-needle Type 402 double locked stitch may be used.

- United States Patent [19.]

Friihlich '[22] Filed:

. DYED SLIDE FASTENER WITH STITCHED-ON COUPLING COIL [75] Inventor:Alfons Friihlich, Essen, Germany [73] Assignee: Opti-Holding AG,Glarus/Schweiz,

' Germany Feb. 18, 1972 211 App]. No.: 227,503

[30] Foreign Application Priority Data Oct. 13, 1971 Germany P 21 51000.9

Oct. 13, 1971 Germany P 21 50999.9

[52] US. Cl 24/205.16 C [51] Int. Cl A441) 19/14 [58] Field of Search24/205.1C, 205.16 C, 24/205.16 R, 205.13 C; 2/265 [56] References CitedUNITED STATES PATENTS 3,022,803 2/1962 Berberich et a1. 24/205.l6 C

Burbank 24/205.1 C

3,484,906 Yoshida 24/205. 1 3 C Primary Examiner-Donald A. GriffinAtt0rney-Karl F. Ross [57] ABSTRACT A coupling coil is lockstitched tothe longitudinal edge of a support tape with a transparentsynthetic-resin mono-filamentary-thread overlying the individual coilturns. The coil and the tape are dyed and the thread is lefttransparent. In this manner the color of the coil is visible through theattachment thread and there is no color contrast apparent between thisthread and the rest of the stringer. Heat treatment of the dyed andassembled stringer flattens the monofilament over the coil to attach thecoil securely to the tape and to make the thread blend in as much aspossible. A single needle Type 401 or a double-needle Type 402 doublelocked stitch may be used.

14 Claims, 8 Drawing Figures SHEET 2 OF 2 1 DYED SLIDE FASTENER WITHSTITCHED ON COUPLING COIL FIELD OF THE INVENTION The present inventionrelates to a slide fastener and a method of making such fastener. Morespecifically this invention concerns a colored slide fastener that isdyed to match the garment in which it is to be installed.

BACKGROUND OF THE INVENTION It is necessary in most garments tocoordinate the color of the various accessories with the fabric of thegarment. To this end slide fasteners are produced in a wide range ofcolors, usually achieved by simply dyeing the fully assembled fastener.

Since the fastener is usually made of three different materialstextilesupport tapes, synthetic-resin coupling elements or coils, andsynthetic-resin or naturalfiber thread interconnecting the tapes andcoils-it has been found extremely difficult to achieve the same degreeof coloration in all of its parts. Dyeing'of the slider is usually foundto be unnecessary, and the end-stop members are either metallic staplesor are made of the same material as the coils.

The color contrast is particularly marked between the thread forming thestitching attaching each coil to its tape, and the coil tape. Thisdifference is most troublesome when spun or twistedmultifilament thread,be it synthetic or natural, is used. Even when the same polyamide orpolyester that is used in the coupling coils is employed for theattachment stitching is this contrast present.

One method of preventing this color difference has been to use onlyslightly stretched or oriented synthetic-resin thread which, although itlackssomething in stability and strength,.tends to have roughly the samedye-absorbing capacities as the tapes and coils. However, theunavoidable differences between the extent of dye absorption in thestitching on one hand and in the coils and'tapes on the other hasgenerally been accepted as inevitable. I

Another solution has been to make the entire fastener out of transparentmaterial. In this case a synthetic-resin textile is used'for thesupport'tapes and the coils are woven into. the'edge ofthe tapes nostitching being used. In order to enhance the transparency of such afastener, as open a weave as possible is used for the tapes. Althoughsuch a. solution has its theoretical merits, the fasteners so made arein reality not satisfactory: they are insufficiently transparent, theyreflect and shine under certain light, and they are physically weak.

OBJECTS OF THE INVENTION SUMMARY OF THE INVENTION These objects areattained according to the present invention by a slide fastener having astringer made of a pair of woven or knitted textile support tapes eachcarrying a coupling coil, and transparent syntheticresin monofilamentarythread overlying the coils and serving to attach them to the tapes. Thecoils and the tapes are dyed but the visible stitching is transparent sothat the color of these tapes and the coils is seen through thestitching.

According to another feature of the present invention the coils arestitched by an upper or needle thread and a looper or locking thread.Only one of these threads overlies the turns of the coils and only thisthread need to be a transparent synthetic-resin monofilament. The otherthread, that one which overlies the tape, may be a multifilamentary spunor twisted thread.

In accordance with another feature of the invention a highly stretchedand oriented monofilament is used as the transparent attachment threadto give two surprising and extremely useful advantages. First such athread is so very dense that the fastener may be dyed with itsstitching, but this stitching will not absorb any dye and will thereforeremain transparent. Second'the fastener can be subjected to heat andpressure after assembly to shrink the monofilament somewhat and flattenit where it passes over the turns of the coupling coil, thereby securelyfastenin'gthe coil on the tape.

Thus the method according to the present invention lies in the steps offorming at least a slide-fastener stringer half by stitching a couplingelement to a support tape with a transparent thread, dyeing the tapesand coupling coil simultaneously, and heating and flattening thetransparent thread on the dyed stringer half. Formation of end-stopmembers and installation of the slider can be carried out before orafter the dyeing or heat-treating steps. Since the visible and flattenedtransparent threads lie directly on the dyed coupling element, colortransmission through them is excellent, much better than in theprior-art fully transparent fasteners. In accordance with furtherfeatures of this invention double locked stitching, corresponding toTypes 401, 402, 403, 404, 405, and 406 of the Federal SpecificationsBoard (Federal Standard 751(a)), is used. In this manner at least twoparallel bights of thread overlie each turn.

DESCRIPTION OF TI-IVEQDRAWING The above and other objects, features, andadvantages will become more readily apparent from the followingdescription, reference being. made to the-acpresent invention;

FIG. 7 is a schematic diagram showing how the stringer of FIGS. 1-4 ismade; and

FIG. 8 is a view corresponding to a detail of FIG. 4 showing theflattened threads.

SPECIFIC DESCRIPTION FIGS 1-4 show a pair of coupling coils 1 made ofsynthetic-resin, here of a Nylon-type polyamide or even a polyester thatcan be dyed. The coils 1 each have a plurality of turns 5 formed byupper and lower shanks 6a and 6b, respectively, with coupling heads andbight portions 6d interconnecting neighboring lower shanks 6b to uppershanks 6a. Each coil 1 is stitched to a support tape 2 that defines aplane 1. These tapes 2 are woven or knitted and can be dyed like thecoils 1. Either synthetic or natural-fiber textile material may be usedfor the tapes.

The straight upper and lower shanks 6a and 6b lie directly over eachother and parallel to each other relative to the plane P. The heads 6care flattened and the bights 6d lie at an angle to the plane P. Similarcoils l and tapes 2 are described in patent application Ser. No. 82,323;Ser. No. 82,334(now U. S. Pat. No. 3,714,683); Ser. No. 82,325 (U.S.Pat. No. 3,685,474); and Ser. No. 82,326 filed jointly by myself, M.L.Cappel, and E. Stiibiger on Oct. 20, 1970.

Each coil 1 is secured to the face of its tape 2 at the edge thereof bylongitudinal stitching 3, 4 comprising a transparent non-dye-absorbingmonofilament looper thread 3 and a multifilament needle thread 4 whichmay or may not absorb dye. A Type 401 double locked or chain stitch isused, so that on sewing the needle pierces the stringer from the tapeside. FIG. 1 shows that this type of stitch will leave three bights 7 oftransparent thread 3 overlying each upper shank 6a, while the point 8where the upper and lower threads 3 and 4 cross is buried in a fillercord 10 running longitudinally through the length of each coil 1. Thelooper thread 3 is never kinked but is only forced to conform at thebights 7 to a diameter of curvature equal to around twice the diameter Dof the needle thread 4.

Since these bights 7 lie snugly over the upper shanks 6a, especially asa result of a subsequent heat treatment which flattens the bights 7 asseen in FIG. 8, the color of the element 1 will be clearly visiblethrough the bights. Even if the thread 3 absorbs some dye, its closeengagement with the coils 1 will still make it blend in completely. 7

Of course the needle thread 4 can also be transparent. FIG. 3 shows howthe single line of stitching of thread 4 is extremely innocuous on thetape side of the fastener.

FIGS. 5 and 6 show a slide-fastener stringer much as described in mycommonly assigned and filed patent application Ser. No. 227,485. A pairof coil-type coupling elements 1 have turns 5' secured to tapes 2' bymeans of a pairof needle threads 4' and a single looper thread 3 of aType 402 stitching. The tapes 2 are each formed with a longitudinal fold9 forming a flap 9a to which the elements 1' are stitched.

In this embodiment however the stitching is done from the coil side ofthe fastener, and then the tape if folded over at 9. Either the needlethread 4' or the looper thread 3' or both can be transparent, dependingon need. In any case due to the relatively wide transverse lay of thelooper thread 3' the fold 9 is maintained for use of the stringer as aninvisible-type slidefastener.

FIG. 7 shows schematically an apparatus for carrying out theslide-fastener construction method according to the present invention.

A pair of tapes 2 are fed from supply bobbins 11 to a sewing station 12.A pair of interleaved coils 1 as well as needle and looper threads 3 and4 are also fed to this station 12 from respective supplies. Adouble-needle sewing machine 13 at the station 12 sews the interleavedcoils 1 to the edges of the parallel tapes 2 according to principleswell known in the art, forming a single-needle double-locked stitch ofType 401 as described above over each coil with the needles piercing thetapes from underneath.

After attachment of the interleaved coils to the tapes with adye-absorbing needle thread 3 and a non-dye absorbing monofilament 4 thecompleted stringer 14 is fed to a dyeing station 15 where it is passedthrough a vat 16 containing textile dye. Subsequently the dyed fastenerwhose monofilamentary looper threads 4 have absorbed no dye are fed to astation 17 where they are pressed between a pair of driven heatedrollers 18 that serve to dye the stringer 14 and to flatten and shrinkthe threads 4 where they overlap the coil turns 5. In this manner a verytight fastener is obtained.

Finally the dyed and heat-treated stringer 14 is lead in the transportdirection T to a station 19 where it is provided with end-stop members,sliders, and where individual slide fateners are cut out of it.

This method produces an excellent coil-type slide fastener which is dyedto blend exactly with whatever color is desired. There is virtually nocontrast between the color of the stitching on one hand and that of thecoupling element and the tape on the other.

I claim:

1. A slide-fastener stringer having a pair of halves each comprising:

a continuous synthetic-resin dyed coupling element having a multiplicityof turns each provided with a head adapted to engage between two similarheads of a similar element;

an elongated dyed tape having one longitudinal edge carrying saidelement; and

stitching attaching said element to said tape and formed from a pair ofinterlocked threads, one of said threads overlying said turns of saidelement and being composed of a transparent syntheticresin monofilament.

2. The stringer defined in claim 1 wherein said one thread isnon-dye-absorbing.

3. The stringer defined in claim 2 wherein said stitching is a singleneedle double-locked stitch, said one thread being the looper thread.

4. The stringer defined in claim 2 wherein said stitching is adouble-needle double-locked stitch, said stitching comprising a pair ofneedle threads overlying said turns and composed of transparentmonofilament.

5. The stringer defined in claim 1 wherein said one of said threads iscolorless.

6. The stringer defined in claim 1 wherein said element, tape andthreads are dyed in common and have the same coloration.

7. The stringer defined in claim 1 wherein said element is a generallyhelical coupling coil, said turns of said coil each having a pair ofcoplanar shanks lying in a plane perpendicular to the axis of the coil,said one of said threads straddling the pairs of shanks.

8. The stringer defined in claim 1 wherein said element is a meander.

9. A method of making a dyed slide-fastener stringer half comprising thesteps of:

simultaneously dyeing a synthetic-resin coupling coil and a textilesupport tape; and

stitching the coupling coil to the longitudinal edge of the support tapewith a transparent synthetic-resin mono-filamentary thread to form astringer half.

10. The method defined in claim 9 wherein said stitching islockstitching with said transparent thread overlying the turns of saidcoil.

bights of said transparent thread overlie each turn of said coil.

14. The method defined in claim 13 wherein said bights lie substantiallyparallel to each other over said turns.

1. A slide-fastener stringer having a pair of halves each comprising: a continuous synthetic-resin dyed coupling element having a multiplicity of turns each provided with a head adapted to engage between two similar heads of a similar element; an elongated dyed tape having one longitudinal edge carrying said element; and stitching attaching said element to said tape and formed from a pair of interlocked threads, one of said threads overlying said turns of said element and being composed of a transparent synthetic-resin monofilament.
 2. The stringer defined in claim 1 wherein said one thread is non-dye-absorbing.
 3. The stringer defined in claim 2 wherein said stitching is a single needle double-locked stitch, said one thread being the looper thread.
 4. The stringer defined in claim 2 wherein said stitching is a double-needle double-locked stitch, said stitching comprising a pair of needle threads overlying said turns and composed of transparent monofilament.
 5. The stringer defined in claim 1 wherein said one of said threads is colorless.
 6. The stringer defined in claim 1 wherein said element, tape and threads are dyed in common and have the same coloration.
 7. The stringer defined in claim 1 wherein said element is a generally helical coupling coil, said turns of said coil each having a pair of coplanar shanks lying in a plane perpendicular to the axis of the coil, said one of said threads straddling the pairs of shanks.
 8. The stringer defined in claim 1 wherein said element is a meander.
 9. A method of making a dyed slide-fastener stringer half comprising the steps of: simultaneously dyeing a synthetic-resin coupling coil and a textile support tape; and stitching the coupling coil to the longitudinal edge of the support tape with a transparent synthetic-resin mono-filamentary thread to form a stringer half.
 10. The method defined in claim 9 wherein said stitching is lockstitching with said transparent thread overlying the turns of said coil.
 11. The method defined in claim 10 wherein said lock-stitching is of the double-locked type.
 12. The method defined in claim 11, further comprising the step of subjecting such transparent thread to heat where it passes over said coil turns.
 13. The method defined in claim 11 wherein three bights of said transparent thread overlie each turn of said coil.
 14. The method defined in claim 13 wherein said bights lie substantially parallel to each other over said turns. 